1. Field of the Invention
The present invention relates generally to thin layer chromatography (TLC) and in particular to a computer enhanced video area densitometer and its application in determining the color composition concentrations of chemical and biological compounds deposited on a variety of different chromatographic and electrophoretic media.
2. Description of Related Technology
Chromatography is one of the most widely used methods of performing specific quantitative analysis in chemistry and biology. In the past, using thin layer chromatography (TLC), the concentrations or densities of compounds present as spots and bands of light-absorbing, fluorescent, or chemiluminescent materials on transparent or translucent supports, such as thin-layer plates, radioautograms, paper chromatograms, electrophoresis gels, etc., have been analyzed using a light intensity scanner. This scanner was typically a mechanical device which moved the transparent or translucent support containing the material under analysis across a light sensor such as a photomultiplier or photocell. The support, holding the material being analyzed, was placed either between a light source and the light sensor, or the light source was placed on the same side as the light sensor for absorbance or reflectance measurements of the material. A mechanical slit was used to focus the light source into a narrow beam.
More recently, the density of a spot of a specimen compound has been determined by using a video camera, video image digitizer, and digital computer to create a videodensitometer. Such videodensitometers did not require mechanical support movement mechanisms, nor focusing apparatus for light beam definition, and enabled an entire field of spots to be measured within a single video scan with a high degree of resolution.
Digital capture of video information has been used for image enhancement and analysis, however, its application in densitometry and analytical biochemistry has been limited due to the relative complexity and high cost of known systems necessary for digital capture of a video image. Previous systems required multiple flames collected at different video scan times to construct the video image. Prior art systems were therefore not well suited for image capture in circumstances where the image quality deteriorated quickly.